A three year research career development program is described for a veterinarian with five years of practice experience and board certification by the American College of Veterinary Pathologists. The program outlined in this proposal will culminate in a Ph.D. degree, preparing the applicant for the initial stages of her research career and submission of a FIRST award/Independent Scientist Award. The hypothesis tested in this proposal is that the major inducible 70 kDa heat shock protein (i.e., hsp72) increases cytopathic effect caused by measles virus (MV) infection of nervous tissues. Hsp72 is induced by diverse physiologic stimuli, including fever, and is a hallmark of the cellular stress response. Preliminary in vitro data show that MV infection induces hsp72, suggesting a role in the support of basal cytopathic effect/replication, whereas elevation of hsp72 at the time infection is initiated results in increased cytopathic effect, characterized by the emergence of large plaque phenotypic variants. Similar large plaque variants have been correlated to enhanced neurovirulence. Results of this work may therefore identify a cellular determinant of MV neurovirulence, as well as a determinant of virulence relevant to several neurotropic viruses since induction of the cellular stress response increases transcription of herpesvirus, HTLV-1, HIV, and canine distemper virus. The hypothesis will be tested in two objectives. In objective I, the role of hsp72 in modulating MV-cell interaction will be examined in astrocytoma and neuroblastoma cell lines. Here, the effect of selective over-expression of hsp72 on viral attachment, penetration, transcription, protein expression, cytopathic effect, and infectious progeny release will determined. Over-expression will utilize stably transfected cell lines containing an inducible hsp72 construct. As a corollary to this approach, the role of virus-induced hsp72 in supporting basal virus replication will be examined by selectively inhibiting hsp72 production. In objective II, the role of hsp72 in modulating MV neurovirulence will be determine by infecting transgenic mice constitutively over-expressing hsp72 with a mouse- adapted hamster neurotropic strain of MV.